The tool is an operation instrument in human medicine. It can be used in the preparation of the osseous support in the implantation of an artificial joint replacement, in particular in the case of knee joints. Endoprostheses are often secured in grooves which are introduced into the bone. The implant is subsequently cemented into the groove or is driven into the groove in a cement-free manner. In particular in the case of the cement-free fastening, the groove in the bone must be prepared very precisely.
In order to increase the precision in the preparation of the groove in the bone, it is also known to fasten a template on the bone, which template has a slit which corresponds in its length and width to the length and width of the groove which is to be sawn out in the bone lying beneath. The known tool, mentioned in the introduction, having the two parallel saw blades at its head, has a width there which corresponds to the width of the groove which is to be sawn out. The length of the saw blades is shorter than the groove which is to be sawn out. The known tool is inserted into a surgical jigsaw, is set by the latter into a linear oscillating movement and is introduced with its saw blades, arranged at the head, into the slit of the template which is fastened on the bone. The head of the tool with the saw blades projects over a guide surface provided on the tool, so that the guide surface rests on the surface of the template when the saw blades have reached a particular depth in the bone. With the known tool, therefore, two parallel slits can be sawn into the bone, the distance of which corresponds to the desired groove width, with their length corresponding to the desired groove length and their depth corresponding to the desired groove depth. Between the two slits, a bone strip remains, running in longitudinal direction of the groove. In the known method, this bone strip is subsequently removed by a hand-operated, depth-limited special chisel. The special chisel must be operated manually in a drawing and pushing manner through the groove, wherein a lateral tilting of the special chisel can occur. The freehand preparation of the groove with the special chisel can consequently lead to an increased variance in the bone groove dimensions. In particular in the case of structural changes to the bone in the region of the groove (osteoschlerosis, calluses, foreign bodies, cysts or osteoporosis), a distinctly altered effort of force can occur during operation of the special chisel, through which the accuracy of preparation is reduced. The known tool is, in addition, only permitted for one-time use, so that for each operation a new saw tool is necessary and thereby high operation costs arise.
It is an object of the present invention to provide a tool for insertion into a surgical saw which has improved characteristics. This object has been achieved by a tool having the features of the claims.